From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 01 Aug 2002 18:19:44 -0700 (PDT) Message-Id: <20020801.181944.09310618.davem@redhat.com> Subject: Re: large page patch From: "David S. Miller" In-Reply-To: <3D49DFD0.FE0DBC1D@zip.com.au> References: <3D49D45A.D68CCFB4@zip.com.au> <20020801.174301.123634127.davem@redhat.com> <3D49DFD0.FE0DBC1D@zip.com.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: akpm@zip.com.au Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, rohit.seth@intel.com, sunil.saxena@intel.com, asit.k.mallick@intel.com List-ID: "David S. Miller" wrote: > This is probably done to increase the likelyhood that 4MB page orders > are available. If we collapse 4MB pages deeper, they are less likely > to be broken up because smaller orders would be selected first. This is leakage from ia64, which supports up to 256k pages. Ummm, 4MB > 256K and even with a 4K PAGE_SIZE MAX_ORDER coalesces up to 4MB already :-) Apparently a page-table based representation could not be used by PPC. The page-table is just an abstraction, there is no reason dummy "large" ptes could not be used which are just ignored by the HW TLB reload code. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/